(a) Field of the Invention
The present invention relates generally to television signal distribution and, more particularly, to methods and systems for combining signals of diverse modulation formats, such as broad-area signals that are broadcast via satellite in one modulation format and local signals that are broadcast terrestrially or via cable in another, different modulation format.
(b) Description of Related Art
Satellite television broadcasting systems typically deliver a large number of television programming channels to system subscribers. Because these channels are broadcast from a centralized distribution location, however, satellite television broadcasting systems generally do not include regional or local television broadcasts (e.g., local newscasts, sportscasts, and weather forecasts) in the broadcasted satellite television signals which are received by a multitude of regions or localities throughout a larger distribution area, such as the entire North American continent. Consequently, off-air or community access television (CATV) distribution networks, which are separate from the satellite distribution network, are often used to deliver the regional or local television broadcasts to individual subscribers in the various regions or localities. The need to provide a separate distribution system for local television can be problematic in multiple-dwelling unit (MDU) buildings, such as apartment buildings and office buildings, where the cost of installing and maintaining a local channel distribution system separate from the satellite broadcast distribution system is especially high.
Moreover, local channel distribution architectures, such as those that are commonly present in typical MDU's, route local television channel signals through cables and amplifiers characterized by significant RF losses, distortion, and other noise to which local off-air and CATV broadcasts (which are typically amplitude-modulated or AM signals) are particularly sensitive.
Further, in a multiple-dwelling environment, there is a practical limit on the number of satellite receiving antennas and local broadcast receiving antennas that may be placed on or about the multiple-dwelling unit. Accordingly, it is generally not practical for the occupant of each dwelling in a multiple-dwelling unit to install satellite and local receiving antennas, so an alternative, shared antenna system would be beneficial for reasons of aesthetics as well as cost.